"Latest estimates by astronomers tell us that the universe is 30 or 40 billion light years in diameter. In layman's terms, that means that it would take light (which travels at the speed of light J) 40 000 000 000 years to cross from one side of the universe to the other!"

"The simple answer is that the observable Universe is about 10 billion light years in radius. That number is obtained by multiplying how old we think the Universe is by the speed of light."

20 billionlight years

The universe that we know is made up of the solar system (sun, moon, and all
of the planets), the stars, the galaxies, and the cosmos. Basically it's everything
that is around us. But how big is it?

The large magnitude of the universe is unimaginable to us humans. To see how
big the universe is, take this into perspective: the diameter of the entire solar
system is about 8,000 million kilometers. The universe itself is about 1026 meters.
The nearest galaxy that is similar to that of earth is Andromeda. That
alone is 1021 meters away. The center of out galaxy is 26,000
light years away from where we are. One light year is equal to almost 10 billion
kilometers. That means in an airplane, it would take billions of years to reach
it.

Modern science says that the known universe extends about 10 billion light
years in all directions, and consists of 200 billion galaxies. This means it can
take light approximately 20 billion years to cross from one side of the universe
to the other. These numbers, however, are only of the known universe. No one knows
exactly how big the universe actually is, or how far it extends.

Carmen Bissessar -- 2002

Bibliographic Entry

Result(w/surrounding text)

StandardizedResult

Macmillan Encyclopedia of Physics. New York: Macmillan, 1996.

"The observable universe extends out to approximatly 10 billion light years away."

20 billionlight years

Milton, Simon. The Oxford Book of Astronomy. New York: Oxford, 1998.

"Diameter of Universe 10^26 (miles)"

16 billionlight years

Asimov, Isaac. The Collapsing Universe. New York: Walker, 1977.

"The nearest qusars are 3 billion light years from earth, while the most remote ones may be 6 times as far."